Containment Impact on Primary Care & Adverse Events Unrelated to COVID-19 in Older Patients and/or With Chronic Diseases

Context and hypothesis: In 2017, 10.7 million people affiliated to the French general health insurance scheme benefited from the "Long Term Affection" scheme that waives copayments related to long-term illness, i.e. 17% of the insured patients. They are mostly patients with chronic diseases requiring a regular medical and allied health and nursing care follow-up. During the SARS-CoV-2 epidemic and containment period since March 17th 2020, the French government's messages were to call the Urgent Medical Assistance Service and not to directly visit the GP except for a teleconsultation. Other countries have adopted the same strategy. Mortality rates due to SARS-CoV-2 infection were dramatically high in older patients and/or with comorbidity. In China, the case fatality rate (CFR) was 15% in patients older than 80 and in the United States, 80% of deaths occurred among adults aged 65 years. The CFR was also high in patients with underlying comorbidities, in particular heart failure, hypertension, respiratory insufficiency and diabetes. Elderly and patients with cardio-metabolic and respiratory chronic diseases therefore needed to be particularly protected during the epidemic.

However, these populations also need close management for preventing acute decompensations of chronic diseases or loss of autonomy. During containment, GPs and other medical/allied health/nurse ambulatory health providers perceived a notable decrease in their daily practice activity, including for their chronic and/or elderly patients who may not have called for a visit and/or did not have access to telemedicine. The French Public Health Agency ("Public Health France") reported a decrease in GPs visits at the start of containment, a decrease in the number of emergency visits and in hospitalizations for cardio and neurovascular diseases.

The investigators postulate that under-attendance of primary care services during the epidemic is associated with over-mortality and morbidity non-related to COVID-19.

Main Objective: To assess over-mortality non-related to COVID-19 during the first containment for SARS-CoV-2 outbreak and at 12 months, in a population of elderly and patients with chronic conditions in France. Over-mortality will be assessed globally and according to baseline individual and contextual characteristics such as area of residence, morbidity burden or socioeconomic position.

Secondary objectives: The secondary objectives concern more specifically the effect of under-attendance of primary care services due to containment, on morbidity and mortality at the end of the 12 months follow-up.

• To measure primary care healthcare utilization during containment in this population. Utilization will be assessed through the secondary endpoints related to ambulatory care.
• To analyze the effect of ambulatory healthcare utilization during the containment on non COVID-related morbidity (through the secondary endpoints related to hospital care) and mortality at the end of follow-up

Method and population:

Experimental design: Retrospective exposed/non-exposed (1:1) cohort study in the French National Health Data System (SNDS).

Endpoints:

• The primary endpoint is non-COVID-19 related mortality.
• The secondary outcome will be the use of primary care during period 1 and will be assessed through the number of consultations, teleconsultations and visits by general practitioners, and paramedical professionals (nurses and physiotherapists).

The use of specialist doctors will also be described.

Main inclusion criteria:

The study population is composed of elderly (aged 70 or older) and adult patients with a long-term illness (ALD).

Exposition to containment is defined as the period between March 17,2020 (beginning of week 12, start of containment) and May 10, 2020 (end of week 19, end of containment). The end of follow-up is set at 12 months after the start of containment, at March 17, 2021.

The non-exposed group is composed of elderly (aged 70 or older) and patients with a long-term illness (ALD) for the 2 years before epidemic (2025-2016).

Observed cases in the exposed group will be compared to expected cases estimated among the non-exposed group, for the entire study population and in sub-groups defined upon area of residence, morbidity status and socioeconomic position.

Sample size: Considering the proportion of older patients (9%), of patients suffering from chronic disease (17%) and the overlap between age and disease prevalence, the investigator expect to include approximately 18 000 000 patients.

Information for participants: Waiver of information for participants Origin of personal health data (source used): "National Health Data System"

Expected results: To quantify over-mortality non-related to COVID-19 risk in elderly and patients with chronic conditions, in order to guide public health policy: adapt government messages, improve GP-follow-up and primary care response for a future health epidemic. To identify risk factors associated with morbimortality, in particular variation of primary care utilization in order to adapt public health policy and messages to both the population and GPs.

Study duration: 30 months